Improve cache busting when a show is updated

[wesbos]

Right now when updating a show .md file is updated, in order to get it to show up on the website there are a few things that need to be done:

1. Rebuild the site (automatic)
2. Log into /admin and click the "Sync changed/New Shows" button. (I thought this was automatic, maybe not?)
3. Clear the entire Redis cache as the query for that show is stuck in redis
4. Now, since the DB didnt have the updated info, the vercel CDN cache now still has the old version of the page. So we need to wait 600 seconds (10 mins) for that to clear. https://github.com/syntaxfm/website/blob/main/src/routes/(site)/show/%5Bshow_number%5D/%5Bslug%5D/%2Bpage.server.ts#L5

What should happen.

1. We edit the .md file
2. The site notices that file changed, and updates the DB with the new info
3. The site clears the redis cache for that show - keys homepage:latest_shows, show:###, and show-og-###

cc @stolinski